Do-While loop

Unlike for and while loops, do-while loops check the truth of the condition at the end of the loop, which means the do block will execute once, and then check the condition of the while at the bottom of the block. Meaning that a do-while loop will always run at least once.

For example this do-while loop will get numbers from user, until the sum of these values is greater than or equal to 50:

int num, sum;
num = sum = 0;

do 
{
  scanf("%d", &num);
  sum += num;

} while (sum < 50);

do-while loops are relatively rare in most programming styles.